1. Field of the Invention
The present invention relates to a hardware arrangement for producing bit combinations by which binary data formats are specified in an asynchronous transmission, and more specifically to such an arrangement which is provided in data circuit-terminating equipment (DCE) for ascertaining the format of data transmitted between the DCE and a data terminating equipment (DTE).
2. Description of the Prior Art
With conventional analog telephony, a modem is a device which takes a digital data do (direct-current) signal and renders it compatible with a standard telephone voice channel.
The modem or digital conditioning device is referred to as data circuit-terminating equipment (DCE). This equipment is provided between user data terminal equipment (DTE) and the telephone voice channel.
As an extended command for automatic calling in CCITT recommendation V.25 bis, a so called SET command may be used in asynchronous transmission. The SET command is comprised of three characters SET plus a control code CR (carriage return). In such an asynchronous transmission between the DCE and the DTE, the SET command is used to detect a format of the data to be transmitted. After detecting the data format, data transmission is implemented using the detected data format.
In such an asynchronous transmission using the SET command, data format is detected using a serial interface LSI (large scaled integration) which is controlled by a software operated CPU (central processing unit).
However, as the data transmission rate increases, the above mentioned software based data format detection is unable to correctly receive the data which immediately follows the SET command.